Preparation of polymer solutions which are free of suspended mechanical particles

Conclusions -- A method of preparing low-concentration polymer solutions which are free of suspended particles in measurements of the molecular characteristics by the light-scattering method has been described.-- The system presented permits one to prepare such solutions directly in the measuring cuvette with monitoring of the concentration and size of residual particles simultaneously with the clean-up.-- Kinetic dependences of concentration and of mean residual particle size on duration of clean-up have been obtained.Translated from Khimicheskie Volokna, No. 5, pp. 3–5, September–October, 1990.     

Characterization of In x Ga1−x As/GaAs quantum-well heterostructures by C-V measurements: Band offsets, quantum-confinement levels, and wave functions

The method of C-V profiling combined with self-consistent solution of Schrödinger’s and Poisson’s equations was used to determine with high precision the absolute values of the conduction-band offsets, energies of quantum-confinement levels, and charge-carrier concentrations in quantum-confinement subbands of In _x Ga_1?x As/GaAs quantum-well heterostructures with In content corresponding to the pseudomorphic growth mode (0 < x < 0.3). A characterization technique based on capacitance measurements is developed, enabling one to determine the main electronic parameters of quantum-confinement heterostructures.     

Simulation of the distribution of radionuclides in the reservoir bed for deep-well injection disposal of acid liquid radioactive waste

A mathematical model was developed for describing the changes in the state of the reservoir bed for dee-well injection disposal of acid liquid radioactive waste. The model considers the multicomponent filtration of the solution in the heterogeneous bed, sorption-desorption of radionuclides, taking into account the dependence of the distribution coefficient on the temperature and pH, as well as radioactive decay, interaction of acids with minerals, radiation-chemical and thermochemical decomposition of the acids, and dynamics of the temperature field, taking into account the convective heat transfer, thermal conductivity, and radiogenic heat release. The results of the simulation of the migration of radionuclides were reported, as well as of the distribution of the acids and the dynamics of the temperature field in the vicinity of the injection well of the site for deep-well injection disposal of the waste from Siberian Chemical Combine. A technogenic barrier is formed in the vicinity of the injection well, hindering the spread of radionuclides in the reservoir bed.     

Magnetostatic surface waves in a ferrite/dielectric/metal-strip-grating structure

The dispersion relation for magnetostatic surface waves in a ferrite/dielectric/metal-strip-grating structure is obtained. It is shown that dispersion of magnetostatic surface waves must be qualitatively the same as in a ferrite/dielectric/metal structure, while the slope of the dispersion curve in the region of backward magnetostatic waves existing in a ferrite/dielectric/grating structure (and in a ferrite/grating structure in particular) is considerably higher than the slope of this curve corresponding to a ferrite/dielectric/metal structure. It is found that this phenomenon can be explained by the dependence of the grating’s shielding capability on the wave number of magnetostatic surface waves. A grating shielding parameter is introduced and dependences of this parameter on the wave number that can be used to explain the phenomena observed in the experiment are determined.